The invention relates to a photographic copying arrangement, in particular, a photographic multipurpose copying apparatus which can, at will, produce exposures of photographic negative or positive copy masters and/or screen copy masters generated by a cathode ray tube (CRT) onto photographic copy material.
In the photofinishing industry of today, along with prints from negative or positive film material, prints must frequently be produced from images stored on electronic media. These can be images from video film or from a so-called "Still Video" system. Even in conventional photography, with positive or negative film, a current trend is to transfer the pictures from the film to an electronic storage medium, making it possible to reproduce images on a TV or a monitor connected to electronic data processing equipment. Special data processing equipment routines may then be used to artistically alter the images, for example, for use in presentations. Early on, devices became known which made it possible to present prints from images on a VDU (Video Display Unit) screen.
Due to the desire to be able to expose negative or positive copy masters and/or screen images onto photographic copy material all in a single device, photographic multipurpose copiers were developed such as the copier disclosed in U.S. Pat. No. 4,742,375. The photographic multipurpose copier of U.S. Pat. No. 4,742,375 is equipped with a conventional exposure arrangement for negative or positive films, and is also equipped with a more advanced exposure arrangement by which VDU screen images can be exposed onto photographic paper. The supplementary exposure arrangement includes a cathode ray tube (hereinafter abbreviated with CRT), a special imaging optical system and adapted filters so as to make it possible to execute the needed exposures for a color print in the three primary colors blue, green and red.
Embodiment variations of this kind of combined equipment have been attempted. In the most expedient and space-saving variant, the CRT is positioned facing the exposure light path at a 90.degree. angle relative to the conventional exposure configuration. The light from the CRT is lead through an accompanying objective and filter and then, by means of a flip-on mirror, the light is directed to the photographic paper. The CRT, the objective, the filter and the flip-on mirror are fastened in the appropriate positions inside the device, and must be adjusted precisely in relation to one another and to the segment of photographic paper being exposed, so that the image pattern projected from the CRT can be exposed onto the photographic paper sharply and in compliance with the desired enlargement size.
While factory-prepared combination equipment can be adjusted by technical personnel in the factory to obtain a proper alignment, using special equipment, this adjustment is relatively hard for service personnel at the assembly site to perform. A subsequent adjustment might become necessary, for example, based on displacements occurring during transport. In addition, many photo laboratories would like to see their existing conventional copying equipment enhanced and fitted with an exposure arrangement for screen copy masters. Needless to say, the equipment is not returned to the manufacturer for this purpose. Rather the copying equipment is rebuilt at the assembly site. For that reason, an overhaul of this type must take place very quickly, so that the equipment can be put back into working order as soon as possible. In the case of the well-known combination equipment, however, all the optical element groups of the additional contact printer configuration must be separately installed and be adjusted accordingly. This is a time-consuming process and involves relatively long down-time of the copier equipment, during which time it is not available for making prints.
Another problem with the known combination equipment configuration lies in the fact that the single optical element groups are arranged in a rather unprotected manner inside the device. For this reason, they can get dusty rather easily, requiring frequent cleaning of the construction groups. As a result of the separate and relatively unprotected configuration of the optical construction components in the supplementary exposure configuration, them is also the danger that extraneous light will enter or escape, particularly aberrant light or stray light, which can have a very negative effect upon the making of prints.